Our overall objectives are: (1) Improve our understanding of the natural course and pathogenesis of retinal and choroidal lesions of benign and malignant hypertension. This is accomplished by detailed serial studies documented by stereo fundus photographs and fluorescein angiograms. These studies will be supplemented by clinicohistopathological correlations using serial paraffin sections, trypsin digest preparations of retinal vessels, electronmicroscopy as well as the use of an animal (primate) model. (2) Develop a simpler and more acceptable classification of hypertensive retinopathy. (3) Obtain additional information about the basic mechanisms of retinal and choroidal vascular disorders which may be relevant to the understanding of some nonhypertensive vascular fundus lesions. (4) Delineate ocular complications of long-term immunosuppressive therapy, particularly the relationship of corticosteroids and cataract formation.